UK patent GB-B-2,202,664 describes an example of an application for a data entry system for the automated ordering of merchandisable items. Merchandisable items are represented in a printed catalogue or other form of list and are associated with bar codes. A merchandise ordering unit comprises a bar code reader with a telephone transmission capability for use in selecting one or more items from the catalogue and transmitting electronically an order for the merchandise to a processing centre over the public telephone network. The orders for the merchandisable items received in this way are processed in the processing centre. As described, the hand held data entry terminal comprises a calculator-like processing unit with a pen-like bar code reader wand electrically connected to the processing unit via a flexible cable. The processing unit includes a display for displaying information and a telephone transmission capability for transmitting captured data via the telephone network. Although this system works well, it is rather bulky and can be somewhat inconvenient in use as it requires two handed operation, one hand for the processing unit and one hand for the wand. Alternatively, if the processing unit is not carried all the time, it needs to be located in a position where the display on the processing unit can be seen and the keys on the processing unit can be operated. It will be appreciated that particularly where the processing unit is being carried in the hand, operation of the keys on it while holding the wand requires considerable dexterity.
European patent application EP-A-0,094,571 describes a self-contained portable data entry terminal positioned within a portable wand-type enclosure. The wand contains a bar code optical reader, signal conditioning electronics, a microprocessor, a memory and a rechargeable battery. The optical reader is operable as a transmitter/receiver so that readout of data stored in the memory is possible. An example of the use of the portable data terminal is described in which captured bar code data can be output from the memory via the optical reader to an optical receiver and from there via an audio coupler to a telephone line for transmission to a remote station. Another example is described where the bar code data relates to items on a menu in a restaurant. Captured menu selections can be output from the memory via the optical reader to an optical receiver and from there via a computer to a printer in a kitchen. Also described is the programming of the portable data entry terminal using an optical transmitter to input data via the optical reader. The wand includes a beeper for indicating the correct reading of a bar code and the current memory loading. The wand described in EP-A-0,094,571 is relatively simple in construction, and although it is readily portable, it does not provide any confirmation of what has been read.
A further portable data entry terminal manufactured by Telxon Corporation is described in an article entitled “Telxon Corporation, Portable Data Collection and Entry Systems” published by McGraw-Hill in 1989 and referenced “R51-832-101 SKU/UPC Marking and Reading Equipment”. The article describes various models of data entry terminals similar to that described in UK patent GB-8-2,202,664. Data from the terminals can be transmitted to a remote station via various telecommunication options including direct connect modems and acoustic couplers. The data entry terminals have a generally rectangular format, similar to a large scientific calculator with a rectangular display and an array of keys. For most models, a separate bar code reader wand is provided which is connected to the data entry terminal via a flexible cable, requiring a two-handed operation as described above. One model PTC-620 has the same basic format as the other terminals, but is described as being for simple applications and features a snap-on reversible head for one-handed operation with either the left or the right hand. However, this terminal is still relatively bulky and cumbersome and in use it is easy inadvertently to operate one or more keys in the array of keys.